[cfe-dev] Explanation of the llvm::PointerIntPair data structure

[kwadwo amankwa]

Hi ,
I'm studying the llvm/clang source I came accross this line ;

97 mutable  llvm::PointerIntPair<const llvm::MemoryBuffer *, 2> Buffer;


in SourceManager.h and I am curious as to the rationale behind using the 
PointerPair data structure ?I read the documentation about bit mangling 
and  I would be greatful if someone could provide an explanation for the 
rationale behind this technique.


thanks ,
que